Re: [syzbot] [kernel?] INFO: task hung in ret_from_fork (4)

[syzbot <syzbot+7c11975a7e4a2735d529@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in nsim_fib_destroy

------------[ cut here ]------------
!list_empty(&data->fib_event_queue)
WARNING: drivers/net/netdevsim/fib.c:1664 at nsim_fib_destroy+0x16f/0x180 drivers/net/netdevsim/fib.c:1664, CPU#0: syz-executor/6953
Modules linked in:
CPU: 0 UID: 0 PID: 6953 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nsim_fib_destroy+0x16f/0x180 drivers/net/netdevsim/fib.c:1664
Code: 80 3c 38 00 74 05 e8 50 f3 0e fb 48 8b bb 58 05 00 00 e8 34 36 93 fc 48 89 df 5b 41 5e 41 5f e9 87 d8 02 fb e8 02 b1 a4 fa 90 <0f> 0b 90 eb 80 e8 f7 b0 a4 fa 90 0f 0b 90 eb 9f 90 90 90 90 90 90
RSP: 0018:ffffc90004477910 EFLAGS: 00010293
RAX: ffffffff8720efde RBX: ffff88805e6dd000 RCX: ffff88807c291e80
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffc90004477880
RBP: 0000000000000000 R08: ffffc90004477887 R09: 1ffff9200088ef10
R10: dffffc0000000000 R11: fffff5200088ef11 R12: ffff88806c29c800
R13: ffff88805a748498 R14: ffff88805e6dd478 R15: dffffc0000000000
FS:  00005555778a8500(0000) GS:ffff888125460000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055576a2b2950 CR3: 0000000035bdc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nsim_dev_reload_destroy+0x2e3/0x490 drivers/net/netdevsim/dev.c:1768
 nsim_drv_remove+0x58/0x170 drivers/net/netdevsim/dev.c:1779
 device_remove drivers/base/dd.c:571 [inline]
 __device_release_driver drivers/base/dd.c:1284 [inline]
 device_release_driver_internal+0x46f/0x860 drivers/base/dd.c:1307
 bus_remove_device+0x34d/0x440 drivers/base/bus.c:616
 device_del+0x527/0x8f0 drivers/base/core.c:3878
 device_unregister+0x21/0xf0 drivers/base/core.c:3919
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline]
 del_device_store+0x2b0/0x370 drivers/net/netdevsim/bus.c:244
 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb61355cece
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffc08c9cfc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00005555778a8500 RCX: 00007fb61355cece
RDX: 0000000000000001 RSI: 00007ffc08c9d050 RDI: 0000000000000005
RBP: 00007fb61363343f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc08c9d050 R14: 00007fb614344620 R15: 0000000000000003
 </TASK>


Tested on:

commit:         a989fde7 Merge tag 'libnvdimm-fixes-7.0-rc5' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118fd3ef980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=7c11975a7e4a2735d529
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17a9b2da580000